# EMF in a half-ring shaped conductor around a solenoid

A half-ring shaped conductor is being placed around a solenoid. This solenoid has a changing magnetic field.

a) There is a current and EMF (Electromagnetic force) in the half-ring shaped conductor b) There is a current but no EMF in the half-ring shaped conductor c) There is no current but there is an EMF in the half-ring shaped conductor d) There is no current but there is no EMF in the half-ring shaped conductor

My thoughts about this: First of all the field outside a solenoid isn't very big in contrast to the field inside the solenoid. But I assume that it can't be neglected. I think there won't be a current as we would need a full ring-shaped conductor for this. I do think that there will be an EMF in the conductor, and this will generate some eddy currents in the conductor. But there will be no "full-on current" so to speak. So I would say the answer is C. Is this correct?

A Little side-question; Is it at all possible for a non-conducting material to have an induced EMF. For example when we move a non-conducting material (ring-shaped) into a magnetic field. The magnetic flux in the ring changes, but will there be an induced EMF? I know that there won't be a current in the loop, but I'm not certain about the EMF.

Thank you very much!

• I think the answer must depend on how the magnetic flux is changing. Although your conclusion that there wouldn't be a current since there isn't a closed path seems reasonable, I think you're forgetting that electrons can "slosh" back and forth along the length of the conductor as in, for example, an antenna. So, how is the magnetic flux changing? Is it a steady change, variable change or even perhaps alternating? – Alfred Centauri Jun 24 '12 at 22:54
• I assume the magnetic field just increases linearly with time – user10088 Jun 25 '12 at 18:48